82 
ANATOMY OF THE HORSE. 
part we call the haunch; while the tibia and fibula, the human 
leg bones, become of this quadruped the basis of the part we 
are in the habit of calling the thigh. 
TIBIA. 
Situation —Between the stifle and the hock. 
Form —Long, straight, prismatic : larger superiorly than infe- 
riorly. 
Direction —Oblique; but contrariwise to the round bone. 
Division —Into body, superior and inferior extremities. 
The body exhibits three faces and three angles. Two of the 
faces are smooth, and are seen anteriorly; one looking outwards, 
the other inwards : the former covered by the extensor pedis, the 
latter by the skin. The posterior face is the broadest, and is 
strongly marked with several longitudinal muscular furrows. 
The anterior angle is rounded off, and below disappears altoge¬ 
ther : the sides are sharpened and roughened by muscular attach¬ 
ment. 
The superior extremity, mor£ bulky and extensive than 
the inferior, exhibits—Superiorly, two irregularly ovoid flattened 
articulatory surfaces, which, by means of intervening cartilages, 
are accommodated to the condyles of the round bone: these are 
parted by a small sharp elevation and two asperous pits, into 
which latter are fixed the crucial ligaments. Anteriorly, a juttingi 
pyramidal tuberosity, from which a rough ridge runs downward 
into the anterior angle of the body, while, above, it ends in a bluni 
asperous point, turned outwards. At the sides are the two lateral 
processes, the external the more projecting, for the lateral liga¬ 
ments. Between the external lateral process and the tuberosity 
is a groove for the passage of the tendon of the extensor pedis 
and below this groove a broad excavated portion of surface 
from which arises the flexor metatarsi. The external condyle ha; 
on its side a small transversely oval excavation, marking th< 
place of junction of the fibula. 
The inferior extremity, flattened and spreading bu 
little wider than the body itself, consists of two deep articula 
grooves, running obliquely from before backwards, and from with 
out inwards, and of three sharpened projections :—one, extendec 
obliquely, forms the partition between the grooves; the other 
form the lateral processes, of which the internal is more promi 
nent than the external, both being roughened exteriorly for th 
lateral ligaments. The external lateral process has a groove 01 
its side, for the passage of the tendon of the peroneus. 
Connexion —With the round bone, above; the os calcis, below 
